Centrifugal separator



2 Sheets-Sheet 1 Filed March 25, 1957 Feb. 16, 1960 E p, TROLAND2,925,177

CENTRIFUGAL SEPARATOR Filed March 25, 1957 2 Sheets-Sheet 2 UnitedStates Patent O CENTRIFUG'AL SEPARATOR Application March 25, 1957,Serial No. 648,054

4 Claims. (Cl. 209-211) This invention relates to a centrifugalseparator for separating solid material from liquid suspensions thereofand pertains more specifically to a safety interlock arrangement forvalves communicating with a sump for the reception of material rejectedby the separator.

It has been the practice to provide a sump at the bottom of acentrifugal separator for receiving material rejected from the separatorat periodic intervals or as often as required by the accumulation ofrejected material in the sump. The entrance to the sump from theseparator is closed and the exit from the sump to the atmosphere is thenopened to permit discharge of the rejected material. With such anarrangement there is a risk that inexperienced or careless workers mightaccidentally open simultaneously both the entrance and the exit to thesump, resulting in the discharge of the entire contents of theseparator. Since such separators frequently are very large, holdinghundreds of gallons of liquid suspension, such accidents may result inmajor damage.

One object of the present invention is to provide a safety interlock forthe entrance and exit valves on the sump of a centrifugal separatorarranged to prevent simultaneous opening of both valves.

' Another object is to provide a safetyinterlock of the type describedin which a fluid pressure system is employed for actuating the valves.

Still another object is to provide a fluid-pressure actuating system forvalves on the sump of a centrifugal separator, the pressure fluid foropening the exit valve being supplied through and controlled byactuating means for closing the entrance valve, the device being soarranged that it is impossible to open the exit valve until the entrancevalve has first been closed.

Afurther object is to provide a device of the type described employing afluid-pressure system for actuating the valves so constructed andarranged that it is impossible after the dumping operation to open theentrance valve until the exit valve has first been closed.

Other and further objects will be apparent from the drawings and fromthe description which follows.

In the drawings:

Fig. l is a view in side elevation, partly broken away and in section,of a centrifugal separator embodying the present invention;

Fig. 2 is a view in vertical section on an enlarged scale of theactuating cylinder and piston for actuating the entrance valve;

Fig. 3 is a schematic view showing the arrangement of pipes, valves andcylinders for controlling the valves with the entrance valve in openposition and the exit valve in closed position; and e i Fig. 4 is a viewcorresponding to Fig. 3 showing the entrance valve in closed positionand the exit valve in open position. fAs appears in Fig. 1, theseparator comprises a generally cylindrical chamber having a tangentialinlet 12 adjacent its upper end and an axial outlet 14 at its upper endfor the accepted material withdrawn from the separator. The separatorhas a conical portion 16 at the lower end of cylindrical portion 10opening into a sump chamber 18 at its bottom. The whole assembly ismounted upon angle iron supporting legs 15, 15.

Disposed within the separator is a valve 20 which is mounted for axialmovement to and from. a raised position as shown in Fig. 1, in which thesump chamber 18 is open to the bottom of the separator, and a loweredposition, in which it seals sump chamber 18 from conical portion 16.Valve 20 is mounted on the end of actuating piston rod 22 slidablyarranged in cylinder 24 which in turn is secured in a housing 26supported from the walls of conical portion 16 by a plurality of hollowstruts 28, 28. A conical baffle 30 may be mounted over cylinder 24 asdisclosed in my co-pending application, Serial No. 586,704 filed May 23,1956. An exit valve or closure 34 is mounted on bracket 36 at the lowerend of sump chamber 18 bracket 36 being pivoted to an angle iron support38 secured to the sideof sump chamber 18 so that closure 34 is adaptedto be swung to and from a closed position in which it seals ofi sumpchamber 18, as shown in Fig. 1, and an open position in which sumpchamber 18 is open to the atmosphere. The means for actuating closure 34includes a linkage 40 pivoted at one end to bracket 36 and at the otherend to a toggle 42 which in turn is pivotally mounted, on angle iron 38and is secured to piston rod 44 slidably mounted in cylinder 46 which ispivotally secured at its upper end to bracket 48 mounted on the side ofsump chamber 18.

Pressure-fluid lines 50, 52, 54 for supplying fluid under pressure tocylinders 24 and 46 are arranged to pass through hollow supportingstruts 28, 28 as shown in Fig. 1. Cylinder 24, as shown in Fig. 2,includes an end closure 56 at its upper end into which fluid-pressureline 50 is threadedly engaged and which acts .as a stop for the upperface 58 of piston 22. Cylinder 24 also includes a closure member 60 atits lower end having a central cavity 62 of reduced diameter which mateswith and receives a corresponding portion 64 of reduced diameter at thelower face of the piston. A passage 66 in the wall of closure member 60communicates with fluidpressure line 54 while a second axially extendingpassage 68 in closure member 60 communicates with fluid-pres sure line52. i

As shown in Figs. 3 and 4, a check valve 70 is provided in line 54between cylinder 46 and cylinder 24, which communicates at one end withthe lower reduceddiameter portion 62 of cylinder 24 as described aboveand at the other end with the lower portion of cylinder 46. Check valve70 is arranged to permit fluid flow through line 54 into cylinder 24 andto prevent flow in the opposite direction. A branch line 72 connects themidpoint of line 54 to needle valve 74, while a separate line 76arranged in parallel with line 52 communicates with the upper end ofcylinder 46. A pressure fluid such as air is supplied to the controlsystem through filter 80, water-trap 82 and pressure regulator and gauge84, the air supply being introduced into a four-way slide valve 86 whichmay be of conventional construction and which includes a tubular housing88 and a slide member including a pair of spaced sealing disks 90, 92rigidly connected together by connecting rod 94. Sealing disks 90, 92are actuated by a plunger rod 96 which in turn is actuated by a solenoidof any conventional vconstruction.

Outlets 100, 102 in the wall of valve 86 vent the interior Aline 110'connected to a source of water under pres sure is led through valve 112into the side wall of sump chamber 18 nearthe top. A branch line 114pro.- vided with pressure-actuated .iiontrol valve 116 summits: cateswith sum'pchamber near its bpttdm. Valve 1 12 is adjusted so" that thereis of water constantly through line 110 into sump' s, while valve 115sea: justed so that flow through line 114 occurs only when the pressurewithin sump 18 is below a piedtermined value.

I a operation of the device, the liquid dispersion is introduced throughinlet 12 under pressure and swirls downwardly around the inner face ofchambers and 16' to form a vortex through the center of which theaccepted material rises to exit through exit pipe 14. Any rejected solidparticles are thrown out of the vortex and pass downwardly into sumpchamber 18 through the entrance valve which is normally maintained openduring operation of the device, valves 20 and 34 being in the positionshown in Figs. 1 and 3. The constant flow of water through line 110 andvalve 112 serves to prevent the rejection of too much material from theSeparator into sump 18' by maintaining a gentle flow of liquid upwardlyfrom sump 18 into conical portion 16. When it is desired to empty andclean out sump chamber 18, slide valve 86 is actuated by means ofplunger 96 to 'the' position shown in Fig. 4, so that the supply of compressed air is brought into communication with passage 106 while passage104 communicates with vent 102. This introduces air under pressurethrough line 50 into the top of cylinder 24, urging piston 22downwardly. Airalso passes through needle valve 74 and line 72 to line54. However, no pressure buildsup in this line or in the bottom portionof cylinder 46 because line 54 is vented through check valve 70 andcavity 62 in the lower part of cylinder 24'through passage 68 and line52 to passage 104 and 102, 7

As piston 22 descends, however, to the position shown in dotted lines inFig; 2 where reduced-diameter portion 64 just enters cavity 62, line 54is sealed off from its vent to the atmosphere so that air pressure cannow begin to build up in the lower portion of cylinder 46. This pressurebuild-up occurs rather slowly because of the restricted rate of flow ofthe air through needle valve 74 so that piston 22 has time to completethe relatively small remaining portion of its travel, thus closingsecurely valve 20 before suflicient pressure has developed in the lowerportion of cylinder 46 to move piston 44 appreciably. As soon as thispressure does build up, however, piston 44 is urged upwardly to openexit valve 34 as shown in Fig. 4, thus permitting the contents of sumpchamber 18 to fall out.

"Water under pressure continues to be introduced through line 110 towash the interior of sump 18 while the liquid dispersion to be separatedcontinues to be introduced through inlet 12 of the main separator andthe rejected material continues to accumulate on the upper face ofnow-closed valve 20 at the bottom of conical portion 16. In addition,when exit valve 34 is opened, the reduced pressure in sump 18 opensvalve 116 and causes a flow of water through line 114 to wash clean theface of valve 34. After sump 18 has been cleaned, valve 86 is actuatedto the position shown in Fig. 3, thus bringing passage 106 intocommunication with vent 100 and bringing passage 104 into communicationwith the supply of air under pressure. The compressed air passes throughpassage 104 and pressure line 76 to the upper end of cylinder 46, urgingpiston 44 downwardly and moving valve or closure 34 to closed positionas shown in Fig. 3. At the same time the compressed air is introducedthrough passage 104 and line 52 to the lower part of cylinder 24.However, the air pressure is so adjusted by means of reduction valve 84that it isinsufiicient to move valve 20 against the hydrostatic headabove it in the separator, i. e., against the pressure drop across valve20 when closure 34 is open to the atmosphere. As water under pressurecontinues to flow through lines 110 and 114 into sump chamber 18, thepressure within the sump chamber builds up. When sufiicient water hasbeen introduced into sump 18 so as to balance a sufliciently largefraction of the pressure on the upperface of valve 20 and thus reducethe pressure drop across the valve, the air prespossible to open valve20 unlessvalve 34 has first beelr closed, thus providing an automaticsafety interlock for the two valves.

Although specific embodiments of the invention have beendescribed'hereiu, it is not intended to limit the invention solelythereto, but to include all of the obvious variations and modificationswithin the spirit and scope of. the appended claims.

I claim:

1. A centrifugal separator having an outlet. communi-f eating with asump for the reception of rejected material and having a first valve atthe entrance, to said sump and a second .valve at the exit thereof tothe atmosphere;-

, said first valve being mounted within said separatoror movement towardand away from said outlet to seal the entrance to saidsump, meansmounted within said separator including a fluid-actuated piston in acylinder for actuatingsaid first valve, means for supplying fluid underlimited pressure to said cylinder, said pressure being limited to only aportion of the pressure required to actuate said first valve against thepressure drop existing across it when said sump is open to theatmosphere, actuating. means for closing said'second valve, and meansfor.in

troducing fluid under pressure into said sumpto decrease the pressuredrop across said first valve after said sec} ond valve has been closedto permit said piston to open said first valve.

2. A centrifugal separator having a bottom outlet communicating with asump-for the reception of rejected mag terial and having a first valvebetween said outlet and said sump and a second valve at the exit of saidsump, said first valve being-mounted for movement within said separatortoward and away from said outlet to seal the connection between saidseparator and sump, means also mounted within said separator comprisinga first fluid: actuated piston mounted in a first cylinder for openingand closing said first valve, 21 second fluid-actru ated piston mountedin a second cylinder for opening and closing said second valve, meansfor supplying fluid under limited pressure to said first cylinder, meansresponsive to the movement of said first piston for supplying fluidunder pressure to said second cylinder to actuate said second pistononly when said first valve is substantially closed, the pressure of thefluid supplied to' said first cylinder being limited to one less thanthat required to open said first valve against the pressure dropnormally occurring across said valve when closed and when said sump isopen to the atmosphere, and means for introducing liquid under pressureinto said sump when both valves are closed to reduce the pressure dropacross said first valve to permit it to be opened.

3. A separator as defined in claim 2 in which the means for supplyingfluid to the second cylinder includes a vent communicating with theatmosphere through the first cylinder, said vvent being closed by theadvance of the first piston in its cylinder. 7 p m 4. A separator asdefined in claim 3 in which a single source is provided for supplyingpressure fluid to both cylinders and said first piston has""a""leadingportion of reduced diameter seating in a corresponding portion of thecylinder of reduced diametensa id vent entering said reduced-diameterportion of the cylinder and being closed by entry of the leading portionof the piston into said reduced-diameter portion.

References Cited in the file of this patent UNITED STATES PATENTS ChanceJan. 10, 1933 Berges July 3, 1945 Davis Sept. 5, 1950 Vissac Feb. 21,1956 Polleys May 7, 1957 FOREIGN PATENTS Canada Nov. 6, 1956

